Pipe Roller,Conveyor Roller,Plastic Injection Steel Molding,Plastic Mold Roller Yangzhou Donglun Industrial Equipment Co., Ltd , https://www.dltubemill.com
At present, the CB-B gear pump is widely used in dump trucks and construction machinery operating mechanisms. Below are common failures and troubleshooting methods for reference.
**1. Causes of Vibration and Noise and Their Solutions**
**(1) Air Ingestion**
①The CB-B gear pump body and both sides of the cover use a hard seal. If the contact surface flatness does not meet the required standards, air can be drawn into the system during operation. Similarly, if the pump cover and pressure cover are directly connected without proper sealing, air can also enter. If the gland is made of plastic, damage or deformation due to temperature changes may cause the seal to loosen, allowing air to enter. To resolve this, if the flatness of the pump body or cover is not up to standard, it can be ground on a flat steel plate using an "8" shaped pattern with fine sand, or on a surface grinder to ensure the flatness does not exceed 5μm. It is also important to maintain perpendicularity between the plane and the hole. For leaks at the pump cover and gland, epoxy adhesive can be used for sealing.
â‘¡ The shaft is typically sealed with a skeleton oil seal. If the locking lip spring becomes loose, the seal is improperly installed, or the lip is damaged or aged, negative pressure on the back end of the seal may cause air intake. This issue can usually be resolved by replacing the seal.
â‘¢ If the fuel tank has insufficient oil or the suction nozzle is not submerged below the oil level, the pump may draw in air. In such cases, more oil should be added to the tank. If the return pipe is exposed above the oil surface, negative pressure within the system might pull air back into the system. Therefore, the return pipe should generally be submerged below the oil level.
â‘£ If the pump is installed too high above the oil surface, especially when the pump speed is low, it may not generate enough vacuum to properly draw in oil, leading to air ingestion. Adjusting the relative height of the pump and the oil surface can solve this problem.
⑤ A clogged or undersized oil filter can increase suction resistance and lead to air being drawn in. Additionally, a larger inlet diameter may also introduce air. Cleaning the filter or selecting a larger capacity one with the appropriate diameter can prevent both air ingestion and noise.
**(2) Mechanical Reasons**
â‘ Vibration and noise can occur if the pump and coupling are not aligned properly. Adjusting the coupling can help reduce these issues.
â‘¡ Contaminants in the oil can enter the pump and cause wear on gears and other components, resulting in noise. Replacing the oil, strengthening the filtration system, and cleaning the pump can help. If the gears are severely worn, they should be repaired or replaced.
â‘¢ Damage or severe wear of internal components can also cause vibration and noise. For example, large errors in tooth profile or pitch, poor meshing between gears, rough tooth surfaces, excessive overhang length, or improper contact area between gears can all contribute to the problem. In such cases, replacing the gears or grinding them may be necessary. Additionally, damage to the needle cage of the bearing, wear on the shaft journal, or wear on the needle roller can lead to poor bearing rotation and mechanical noise. Disassembling the pump and replacing the bearings may be required.
â‘£ If the gear assembly gap is too small, or if burrs were not removed before assembly, the sliding surfaces between the gear end face and the front and rear covers may become damaged, causing internal leakage and reduced output flow. Dirt entering the pump and wedging into the gap between the gear end face and the end caps can also cause high and low pressure cavities to communicate, reducing flow rate. To address this, disassemble the pump, grind the gear end face to increase the axial clearance, polish the end faces of the front and rear covers and the gears, and remove any burrs (without chamfering). After grinding, the depth of the unloading grooves on the end face of the end cap may vary, so the width should be appropriately increased.